Tuberculosis test kit cobas® MTB-RIF/INH

diagnosticMycobacterium tuberculosisChlamydia trachomatis

Overview
cobas® MTB-RIF/INH for use on the cobas® 5800/6800/8800 systems is an automated, qualitative in vitro diagnostic test that uses real-time PCR for direct detection of rifampicin-resistance associated mutations in the rpoB gene and isoniazid-resistance associated mutations in the katG and inhA genes of Mycobacterium tuberculosis from human respiratory specimens. The test is intended as a reflex assay alongside cobas® MTB and in conjunction with culture and drug susceptibility testing to aid in diagnosis of multidrug-resistant M. tuberculosis (MDR-TB).

Intended use
For analysis of raw sputum, and digested/decontaminated (N-acetyl-L-cysteine/NaOH) sputum and bronchial alveolar lavage (BAL) samples that are MTB-positive by cobas® MTB.

Principle / Method
Sample liquefaction and mycobacterial inactivation are achieved using cobas® Microbial Inactivation Solution (MIS), followed by sonication. The cobas® 5800/6800/8800 systems perform fully automated sample preparation (nucleic acid extraction and purification), real-time PCR amplification and detection, and automated result assignment (positive, negative, invalid).

Sample preparation and extraction
Nucleic acid release is achieved by chemical (MIS, cobas® omni Lysis Reagent), enzymatic (proteinase) and physical (sonication) disruption. Released nucleic acid binds to the silica surface of added magnetic glass particles; impurities and PCR inhibitors are removed by wash steps and purified nucleic acid is eluted at elevated temperature.

PCR and detection
Target-specific primers amplify genomic regions. Mutation-specific probes labeled with fluorescent reporters enable simultaneous detection of MTB complex, rifampicin-resistance and isoniazid-resistance in five detection channels (rifampicin mutations detected in three channels). The master mix contains dUTP (in place of dTTP) and AmpErase (uracil-DNA glycosylase) to control carry-over contamination. Real-time detection measures reporter fluorescence during PCR.

Targets detected

• MTB complex (single-copy genomic target)
• Rifampicin-resistance associated mutations (rpoB gene) — 18 mutations detected
• Isoniazid-resistance associated mutations (katG gene and inhA promoter region) — 7 mutations detected

Intended instruments / workflow
Intended for use on cobas® 5800, cobas® 6800 and cobas® 8800 systems. The systems provide automated sample handling, nucleic acid extraction, PCR amplification, detection and automated result reporting.

Ordering information
Material number | Material description
09040617190 | KIT COBAS 58/68/8800 MTB-RIF/INH 192T

Regulatory disclaimer
For in vitro diagnostic use.